Using $2.25\times10^{ 8}$ $J/\psi$ events collected with the BESIII detector at the BEPCII storage rings, we observe for the first time the process $J/\psi\rightarrow p\bar{ p}a_{ 0}(980)$, $a_{ 0}(980)\rightarrow \pi^{ 0}\eta$ with a significance of $6.5\sigma$ ($3.2\sigma$ including systematic uncertainties). The product branching fraction of $J/\psi\rightarrow p\bar{ p}a_{ 0}(980)\rightarrow p\bar{ p}\pi^{ 0}\eta$ is measured to be $(6.8\pm1.2\pm1.3)\times 10^{ -5}$, where the first error is statistical and the second is systematic. This measurement provides information on the $a_{ 0}$ production near threshold coupling to $p\bar{ p}$ and improves the understanding of the dynamics of $J/\psi$ decays to four body processes.
Categories: hep-ex